Buggy code:
} break ; case CompletionParser . K_INSIDE_RETURN_STATEMENT : if ( ( topKnownElementInfo ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( this . bracketDepth ) ) { popElement ( CompletionParser . K_INSIDE_RETURN_STATEMENT ) ; } break ; case CompletionParser . K_INSIDE_ASSERT_STATEMENT : if ( ( topKnownElementInfo ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( this . bracketDepth ) ) { popElement ( CompletionParser . K_INSIDE_ASSERT_STATEMENT ) ; } break ; case CompletionParser . K_INSIDE_BREAK_STATEMENT : if ( ( topKnownElementInfo ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( this . bracketDepth ) ) { popElement ( CompletionParser . K_INSIDE_BREAK_STATEMENT ) ; } break ; case CompletionParser . K_INSIDE_CONTINUE_STATEMENT : if ( ( topKnownElementInfo ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( this . bracketDepth ) ) { popElement ( CompletionParser . K_INSIDE_CONTINUE_STATEMENT ) ; } break ; } break ; case TerminalTokens . TokenNamereturn : pushOnElementStack ( CompletionParser . K_INSIDE_RETURN_STATEMENT , this . bracketDepth ) ; break ; case TerminalTokens . TokenNameMULTIPLY : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . MULTIPLY ) ; break ; case TerminalTokens . TokenNameDIVIDE : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . DIVIDE ) ; break ; case TerminalTokens . TokenNameREMAINDER : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . REMAINDER ) ; break ; case TerminalTokens . TokenNamePLUS : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . PLUS ) ; break ; case TerminalTokens . TokenNameMINUS : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . MINUS ) ; break ; case TerminalTokens . TokenNameLEFT_SHIFT : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . LEFT_SHIFT ) ; break ; case TerminalTokens . TokenNameRIGHT_SHIFT : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . RIGHT_SHIFT ) ; break ; case TerminalTokens . TokenNameUNSIGNED_RIGHT_SHIFT : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . UNSIGNED_RIGHT_SHIFT ) ; break ; case TerminalTokens . TokenNameLESS : switch ( previous ) { case TerminalTokens . TokenNameDOT : pushOnElementStack ( CompletionParser . K_PARAMETERIZED_METHOD_INVOCATION ) ; break ; case TerminalTokens . TokenNamenew : pushOnElementStack ( CompletionParser . K_PARAMETERIZED_ALLOCATION ) ; break ; } pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . LESS ) ; break ; case TerminalTokens . TokenNameGREATER : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . GREATER ) ; break ; case TerminalTokens . TokenNameLESS_EQUAL : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . LESS_EQUAL ) ; break ; case TerminalTokens . TokenNameGREATER_EQUAL : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . GREATER_EQUAL ) ; break ; case TerminalTokens . TokenNameAND : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . AND ) ; break ; case TerminalTokens . TokenNameXOR : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . XOR ) ; break ; case TerminalTokens . TokenNameOR : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . OR ) ; break ; case TerminalTokens . TokenNameAND_AND : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . AND_AND ) ; break ; case TerminalTokens . TokenNameOR_OR : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . OR_OR ) ; break ; case TerminalTokens . TokenNamePLUS_PLUS : pushOnElementStack ( CompletionParser . K_UNARY_OPERATOR , OperatorIds . PLUS_PLUS ) ; break ; case TerminalTokens . TokenNameMINUS_MINUS : pushOnElementStack ( CompletionParser . K_UNARY_OPERATOR , OperatorIds . MINUS_MINUS ) ; break ; case TerminalTokens . TokenNameTWIDDLE : pushOnElementStack ( CompletionParser . K_UNARY_OPERATOR , OperatorIds . TWIDDLE ) ; break ; case TerminalTokens . TokenNameNOT : pushOnElementStack ( CompletionParser . K_UNARY_OPERATOR , OperatorIds . NOT ) ; break ; case TerminalTokens . TokenNameEQUAL_EQUAL : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . EQUAL_EQUAL ) ; break ; case TerminalTokens . TokenNameNOT_EQUAL : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . NOT_EQUAL ) ; break ; case TerminalTokens . TokenNameinstanceof : pushOnElementStack ( CompletionParser . K_BINARY_OPERATOR , OperatorIds . INSTANCEOF ) ; break ; case TerminalTokens . TokenNameQUESTION : <START_BUG> if ( previous != ( TerminalTokens . TokenNameLESS ) ) { <END_BUG> pushOnElementStack ( CompletionParser . K_CONDITIONAL_OPERATOR , CompletionParser . QUESTION ) ; } break ; case TerminalTokens . TokenNameCOLON : if ( ( ( topKnownElementKind ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( CompletionParser . K_CONDITIONAL_OPERATOR ) ) && ( ( topKnownElementInfo ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( CompletionParser . QUESTION ) ) ) { popElement ( CompletionParser . K_CONDITIONAL_OPERATOR ) ; pushOnElementStack ( CompletionParser . K_CONDITIONAL_OPERATOR , CompletionParser . COLON ) ; } else { if ( ( topKnownElementKind ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( CompletionParser . K_BETWEEN_CASE_AND_COLON ) ) { popElement ( CompletionParser . K_BETWEEN_CASE_AND_COLON ) ; } else { popElement ( CompletionParser . K_BETWEEN_DEFAULT_AND_COLON ) ; } } break ; case TerminalTokens . TokenNameif : pushOnElementStack ( CompletionParser . K_BETWEEN_IF_AND_RIGHT_PAREN , bracketDepth ) ; break ; case TerminalTokens . TokenNameelse : if ( ( topKnownElementKind ( CompletionParser . COMPLETION_OR_ASSIST_PARSER ) ) == ( CompletionParser . K_CONTROL_STATEMENT_DELIMITER ) ) { popElement ( CompletionParser . K_CONTROL_STATEMENT_DELIMITER ) ; } break ; case TerminalTokens . TokenNamewhile : pushOnElementStack ( CompletionParser . K_BETWEEN_WHILE_AND_RIGHT_PAREN , bracketDepth ) ; break ; case TerminalTokens . TokenNamefor : pushOnElementStack ( CompletionParser . K_BETWEEN_FOR_AND_RIGHT_PAREN , bracketDepth ) ; break ; case TerminalTokens . TokenNameswitch : pushOnElementStack ( CompletionParser . K_BETWEEN_SWITCH_AND_RIGHT_PAREN , bracketDepth ) ; break ; case TerminalTokens . TokenNamesynchronized : pushOnElementStack ( CompletionParser . K_BETWEEN_SYNCHRONIZED_AND_RIGHT_PAREN , bracketDepth ) ; break ; case TerminalTokens . TokenNameassert : pushOnElementStack ( CompletionParser . K_INSIDE_ASSERT_STATEMENT , this . bracketDepth ) ; break ; case TerminalTokens . TokenNamecase : pushOnElementStack ( CompletionParser . K_BETWEEN_CASE_AND_COLON ) ; break ; case TerminalTokens . TokenNamedefault : pushOnElementStack ( CompletionParser . K_BETWEEN_DEFAULT_AND_COLON ) ; break ; case TerminalTokens . TokenNameextends : pushOnElementStack ( CompletionParser . K_EXTENDS_KEYWORD ) ; break ; case TerminalTokens . TokenNamebreak : pushOnElementStack ( CompletionParser . K_INSIDE_BREAK_STATEMENT , bracketDepth ) ; break ; case TerminalTokens . TokenNamecontinue : pushOnElementStack ( CompletionParser . K_INSIDE_CONTINUE_STATEMENT , bracketDepth ) ;

Fix:
if ( ( previous != ( TerminalTokens . TokenNameLESS ) ) && ( previous != ( TerminalTokens . TokenNameCOMMA ) ) ) {